Battery output is oscilating around 400w after the SOC reached 100%

[AlbRoehm]

Hey, I'm not sure if this is a configuration, software or hardware issue, so sorry if this is the wrong place, if so please tell me if there is a better place for this. In general, I'm grateful for any information :)

I have successfully set up noah-mqtt and am currently running 3 panels (3* 500wp), a noah 2000 and an apsystems ez1-m inverter. Now that I'm getting all these values from noah-mqtt, I'm seeing things that I think are somehow wrong. As soon as the noah reaches 100% soc, the overspill is not sent all the way to the house, it is throttled. Instead of going through, I see this ‘oscillating’ pattern around 400W. (on the graph ~13:30 - ~14:30)

Maybe any of you have encountered something similar. I disconnected the battery last night and now I see that the inverter is running fine with just the modules connected. Just a stupid wild guess is that the growatt board is not sure whether it still wants to load the battery?

[AlbRoehm]

Or is this maybe only the loading logic that as soon as the tiniest amount is missing it tries to recharge?
Maybe this could be avoided with setting the charge limit to something really low as soon as "full charged" is reached. Some some sort of hysteresis logic ...

[EnterTheMaelstrom]

Do you have one or two Noah batteries? If you have two or more, only the panels on the top one will be sent to your grid when your battery is full. The other one(s) are shut off or only used to recharge the battery.

[AlbRoehm]

Hey, i only have one battery and currently 3 panels connected (2 with a y split).

[MiNi33]

Hi, i have allmost the same setup as @AlbRoehm (only 2 panels 430 Wpeak) and experience the same behaviour. I expect you’re setting for noah_2000_system_output_power is 0 at that moment?
Not shure if this is caused by only the Noah or by the communication between Noah and EZ1.
Growatt states that the EZ1 is a compatible inverter…

(At this moment I’m more troubled by the fact the EZ1 is sometimes unreachable, so that I can’t set it for net zero.)

[AlbRoehm]

At that time the noah_2000_system_output_power was set to 100W and no time schedule was set in the Growatt app.
I also did not set anything on the EZ1. From my current point of view you can always set the EZ1 to max output and it does not really matter wether it's connected. It will always just take what the Battery outputs and throttling at the EZ1 is only wasting the energy.

I could not verify my theory with the hysteresis behavior since I needed to move the panels to their "final" position and i thought i give the "smart mode" a try connecting the shine-app with the my shelly. It's my least preferred option since i wanted to keep my data to myself, but since this seems not possible with the Growatt battery to realize a smart output mode without connecting to their cloud anyways (and the limitations of the query frequency) ... why not go all in and let them show if they do it correctly. 🤷 Not really sure where to go from here. I guess i will just see how it performs with all 4 panels added and some more sun in Summer.

Edit: Seems like the smart mode is doing the same thing

System Output Power = 800W
EZ1 Max = 800W